Pin the curated brief across refresh (stable, not dynamic)

Persisting only 'dismissed' kept swapped-away stories out but let the brief
recompose on refresh — so a chosen replacement (and the hero) could change
unexpectedly. Now the reader's actual brief view is persisted per day:
- loadToday keeps the saved view for the same brief_date (swaps and hero hold
  steady); re-fetches fresh on a new day or when forced.
- A boundary change forces a fresh re-fetch (and re-pins); Replace pins the new
  view; Clear-session drops the pin so it re-composes fresh.

Frontend only — rebuild + refresh (no server restart needed).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/routes/+page.svelte

@@ -23,6 +23,7 @@
   const SEEN_KEY = 'goodnews:seen';
   const DISMISSED_KEY = 'goodnews:dismissed';
   const HISTORY_KEY = 'goodnews:history';
+  const BRIEF_VIEW_KEY = 'goodnews:brief_view'; // {date, items} — the reader's curated brief
   const HISTORY_CAP = 200;
 
   let seenIds = new Set();
@@ -53,8 +54,9 @@
     dismissed = new Set();
     history = [];
     persistSession();
+    P.saveJSON(BRIEF_VIEW_KEY, null); // drop the pinned brief so it re-composes fresh
     showHistory = false;
-    select(selected);
+    select(selected, true);
   }
 
   let filtersOn = $derived(P.active(userPrefs));
@@ -69,17 +71,31 @@
     return P.param(merged);
   }
 
-  async function select(key) {
+  async function loadToday(fresh) {
+    const q = P.param(userPrefs);
+    const ex = Array.from(dismissed).join(',');
+    const fetched = await getJSON(`/api/brief?limit=7${q ? '&' + q : ''}${ex ? '&exclude=' + ex : ''}`);
+    const view = P.loadJSON(BRIEF_VIEW_KEY, null);
+    // On a plain (re)load, keep the reader's curated view for the same day — so
+    // swaps and the hero hold steady. Re-fetch fresh on a new day's brief, or
+    // when forced (e.g. a boundary changed and must be re-applied).
+    if (!fresh && view && view.date === fetched.brief_date && Array.isArray(view.items) && view.items.length) {
+      brief = { brief_date: view.date, title: fetched.title, items: view.items };
+    } else {
+      brief = fetched;
+      P.saveJSON(BRIEF_VIEW_KEY, { date: fetched.brief_date, items: fetched.items });
+    }
+    remember(brief.items);
+  }
+
+  async function select(key, fresh = false) {
     selected = key;
     error = '';
     try {
       // Today = the day's highlights (hero + six). Other moods reveal that
       // category only when chosen.
       if (key === 'today') {
-        const q = P.param(userPrefs);
+        await loadToday(fresh);
-        const ex = Array.from(dismissed).join(',');
-        brief = await getJSON(`/api/brief?limit=7${q ? '&' + q : ''}${ex ? '&exclude=' + ex : ''}`);
-        remember(brief.items);
       } else {
         const mood = moods.find((m) => m.key === key);
         const q = P.param(P.merge(userPrefs, mood?.filter ?? {}));
@@ -96,7 +112,7 @@
   function refreshPrefs() {
     userPrefs = { ...userPrefs };
     P.save(userPrefs);
-    select(selected);
+    select(selected, true); // boundaries changed — re-fetch so they apply
   }
   function applyAction(kind, value) {
     P[kind]?.(userPrefs, value);
@@ -139,6 +155,8 @@
       if (i >= 0) {
         brief.items[i] = repl;
         brief = { ...brief, items: [...brief.items] };
+        // Pin the swap so this exact curated brief survives a refresh.
+        P.saveJSON(BRIEF_VIEW_KEY, { date: brief.brief_date, items: brief.items });
       }
     } else {
       const i = feed.findIndex((a) => a.id === article.id);